This application claims the benefit of Korean Patent Application No. 2002-25399, filed on May 8, 2002, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to a method of fabricating a probe for a scanning probe microscope (SPM) having a field effect transistor (FET) channel structure, and more particularly, to a method of fabricating a probe for an SPM in order to easily fabricate a nano-device.
2. Description of the Related Art
Nowadays, as demands of small products, such as mobile communication terminals and electronic notebooks, increase, the need for small-sized and highly integrated nonvolatile recording media also increases. Since it is difficult to reduce the size of existing hard disks and to highly integrate flash memories, information storage apparatuses using scanning probes and methods thereof have been studied.
Probes can be utilized in various SPM technologies, for example, a scanning tunneling microscope (STM) for reproducing information by detecting currents that flow according to the difference between a voltage applied to a probe and a voltage applied to a specimen, an atomic force microscope (AFM) using an atomic force between a probe and a specimen, a magnetic force microscope (MFM) using a force between a magnetic field of a specimen and a magnetized probe, a scanning near-field optical microscope (SNOM) improving a limit in resolution due to the wavelength of visible rays, and an electrostatic force microscope (EFM) using static electricity between a specimen and a probe.
In order to record and reproduce high-density information at high speed by using the SPM technologies, surface charges existing in a small area of tens of nanometers should be detected. In addition, a cantilever of an array shape should be manufactured in order to improve recording and reproducing speeds.
FIGS. 1A and 1B are a perspective view and an enlarged view of a probe for an SPM having an FET channel structure according to Korean Patent No. 2001-45981.
Referring to FIG. 1A, a bar-shape probe 10 formed by etching a semiconductor substrate 20 is protruded from the substrate 20, and electrode pads 20a and 20b are arranged at both sides of an end portion where the probe 10 and the substrate 20 are connected.
Referring to FIG. 1B, an enlarged view of portion A in FIG. 1A, source and drain regions 11 and 13 are formed on an inclined surface at the end of a V-shape tip of the probe 10. In addition, a channel region 12 is formed between the source and the drain regions 11 and 13.
Since the tip of the probe is located at the end of a cantilever, it is difficult to manufacture an array-shape cantilever and the tip having a radius of tens of nanometers. In a conventional method, a tip having a radius of tens of nanometers is manufactured using various processes, such as an oxidation process, so that the tip is vertically formed on the cantilever.
However, the precision of a photolithographic process deteriorates when a tip having a height of several micrometers is formed, so it is difficult to form source and drain regions having a short channel length. In addition, even when the short channel length is realized using a diffusion process, it is difficult to align the center of the short channel at the end of the tip due to an alignment error in the photolithographic process.